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     <td><h1 class="pagetitle">Bi-directional Override</h1>
         <b><a href="../../../misc/suppkey.htm">Support Key:</a></b> 
         [<span class="ns">2</span>|<span class="ns">3</span>|<span class="ns">3.2</span>|<b><i class="fs">4</i></b>] 
         [<b class="s">X1</b>|<b class="s">X1.1</b>]
         [<b><i class="fs">IE5B2</i></b>|<span class="ns">M</span>|<b class="s">N6B1</b>|<b class="s">O4</b>]</td>
     <td><a href="#what">What is it?</a><br>
         <a href="#attrib">Attributes</a><br>
         <a href="#example">Tag Example</a>
     </td>
     <td><a href="#model">Parent/Content Model</a><br>
         <a href="#tips">Tips &amp; Tricks</a><br>
         <a href="#peculiar">Browser Peculiarities</a></td>
</tr>
<tr><td align=center colspan=3>
<font size=2>= <span class="sitetitle">Index DOT Html</span> by <a href="../../../misc/email.htm">Brian Wilson</a> =</font>
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   <th colspan=3 valign=bottom class="field"><big><u><b
       class="colheaders">&#160;&#160;&#160;Quick Statistics&#160;&#160;&#160;</b></u></big><br></th>
</tr>
<tr><th align=left><b class="l3heading"><a href="../stats.htm#et">End Tag:</a></b><br></th>
    <td rowspan=7>&nbsp;&nbsp;</td>
    <td><span class="magicword">Required</span></td></tr>
<tr><th align=left><b class="l3heading"><a href="../stats.htm#std">Standards Details:</a></b><br></th>
    <td>In all HTML 4.x/XHTML DTDs</td></tr>
<tr><th align=left><b class="l3heading"><a href="../stats.htm#xhtm">XHTML Modules:</a></b><br></th>
    <td><b class=alert>Bi-directional Text</b></td></tr>
<tr><th align=left valign=top><b class="l3heading"><a href="../stats.htm#disp">CSS 'display' Type:</a></b><br></th>
    <td>"<b class="alert">inline</b>"</td></tr>
<tr><th align=left valign=top><b class="l3heading"><a href="../stats.htm#css">CSS Mapping:</a></b><br></th>
    <td><span class="property"><a href="../../../css/properties/intl/unibidi.htm">unicode-bidi</a></span>,
       <span class="property"><a href="../../../css/properties/intl/direction.htm">direction</a></span></td></tr>
<tr><th align=left><b class="l3heading"><a href="../stats.htm#rnd">Default Rendering:</a></b><br></th>
    <td>NA</td></tr>
<tr><th align=left><b class="l3heading"><a href="../stats.htm#w3docs">Official Docs:</a></b><br></th>
    <td><a href="http://www.w3.org/TR/html401/struct/dirlang.html#h-8.2.4">HTML 4.x</a>, 
        <a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_bdomodule">XHTML 1.1</a></td></tr>
</table>
</td></tr>
</table>

<br>
<a name="what"></a>
<dl>
<dt><big><b class="mainheading">What is it?</b></big>
    <dd>Many languages (including Latin alphabet based languages)
        are written and rendered horizontally from left to right,
        while some others (such as Arabic and Hebrew) are written and
        rendered from right to left. When characters from both writing
        systems are present, it is known as bi-directional text (also
        known as BIDI.) Some character combinations in BIDI situations
        are ambiguous with respect to the directionality of the content.
        <br><br>

        If the ambiguity is not made clear, it can be impossible for a
        computer to render these character combinations in such a way
        that the original meaning is conveyed. HTML has allowed for the
        resolution of this problem by creating the BDO element. This
        element is used to force the directionality of each character
        within to the value of its DIR attribute, irrespective of the
        characters' intrinsic directional properties. The BDO DIR attribute 
        specifies whether the override is left-to-right or right-to-left.
         <br><br>

        BIDI override is needed where absolute control over character
        sequence order is required (such as mixed-language directionality
        words) and use of the common attribute DIR on other elements
        fails to produce proper bi-directional rendering. It is also useful
        in dealing with short pieces of text in which the directionality
        cannot be clearly resolved from the surrounding context.
</dl>


<a name="attrib"></a>
<dl>
<dt><br><big><b class="mainheading">Common Attributes</b></big>
<dt><b class="subheading">%<a href="../attributes/core.htm">Core</a>%</b>
    <dd>[<span class="ns">2</span>|<span class="ns">3</span>|<span class="ns">3.2</span>|<b><i class="fs">4</i></b>] 
        [<b class="s">X1</b>|<b class="s">X1.1</b>]
        [<b><i class="fs">IE5B2</i></b>|<span class="ns">M</span>|<b class="s">N6B1</b>|<b class="s">O4</b>]

<dt><b class="subheading">%<a href="../attributes/accessibility.htm">Accessibility</a>%</b>
    <dd>[<span class="ns">2</span>|<span class="ns">3</span>|<span class="ns">3.2</span>|<b><i class="fs">4</i></b>] 
        [<b class="s">X1</b>|<b class="s">X1.1</b>]
        [<b><i class="fs">IE5</i></b>|<span class="ns">M</span>|<b class="s">N6</b>|<b class="s">O5</b>]

<dt><b class="subheading">%<a href="../attributes/events.htm">Events</a>%</b>
    <dd>[<span class="ns">2</span>|<span class="ns">3</span>|<span class="ns">3.2</span>|<span class="ns">4</span>] 
        [<b><i class="fs">X1</i></b>|<span class="ns">X1.1</span>]
        [<b><i class="fs">IE5B2</i></b>|<span class="ns">M</span>|<b class="s">N6B1</b>|<b class="s">O4</b>]

<dt><b class="subheading">%<a href="../attributes/editing.htm">Editing</a>%</b>
    <dd>[<span class="ns">2</span>|<span class="ns">3</span>|<span class="ns">3.2</span>|<span class="ns">4</span>] 
        [<span class="ns">X1</span>|<span class="ns">X1.1</span>]
        [<b><i class="fs">IE5.5</i></b>|<span class="ns">M</span>|<span class="ns">N</span>|<span class="ns">O</span>]

<dt><br><big><b class="mainheading">Specific Attributes</b></big>
<dt><b class="subheading">Dir</b>
<dt>[<span class="ns">2</span>|<span class="ns">3</span>|<span class="ns">3.2</span>|<b><i class="fs">4</i></b>] 
    [<b class="s">X1</b>|<b class="s">X1.1</b>]
    [<b><i class="fs">IE5B2</i></b>|<span class="ns">M</span>|<b class="s">N6.1</b>|<span class="ns">O</span>]
    <dd><b class="l3heading"><a href="../stats.htm#std">Standards Details:</a></b> 
        In all HTML 4.x/XHTML DTDs
    <dd><b class="l3heading">Required?</b> Yes
    <dd><b class="l3heading">Description:</b><br>
        On block-level elements, the DIR attribute indicates the base directionality 
        of the text in the block. If omitted it is inherited from the parent element. 
        The default directionality of the overall HTML document is left-to-right. 
        On inline elements, it makes the element start a new directional embedding 
        level. If omitted, the inline element does not start a new embedding level.
    <dd><b class="l3heading">Values:</b>
        <b class="alert">ltr</b> (Left to Right) | <b class="alert">rtl</b> (Right to Left)

<dt><b class="subheading">Language</b>
<dt>[<span class="ns">2</span>|<span class="ns">3</span>|<span class="ns">3.2</span>|<b><i class="fs">4</i></b>] 
    [<b class="s">X1</b>|<span class="ns">X1.1</span>]
    [<b><i class="fs">IE5B2</i></b>|<span class="ns">M</span>|<b class="s">N6.1</b>|<span class="ns">O</span>]
    <dd><b class="l3heading"><a href="../stats.htm#std">Standards Details:</a></b> 
        In all HTML 4.x/XHTML 1.0 DTDs. Dropped in XHTML 1.1 in favor of XML:Lang attribute.
    <dd><b class="l3heading">Required?</b> No
    <dd><b class="l3heading">Description:</b><br>
        Specifies a string indicating the language/character set used in the BDO container.
    <dd><b class="l3heading">Values:</b> Any <a href="http://www.rfc-editor.org/rfc/rfc1766.txt">RFC 1766</a> value.
        [Must begin with a letter ([A-Za-z]), followed by any number of characters in [A-Za-z0-9-_:.] 
</dl>


<a name="example"></a>
<dl>
<dt><big><b class="mainheading">Example</b></big>
    <dd><div class="example">Does this look &lt;<b class="tagname">bdo</b>
        <span class="tagattrib">dir</span>=&quot;rtl&quot;&gt;Backwards&lt;/<b
        class="tagname">bdo</b>&gt; to you?</div>
</dl>


<a name="model"></a>
<dl>
<dt><big><b class="mainheading">Parent Model</b></big>
    <dd><b class="alert">%<a href="../shorthands.htm#inlineparent">In-line Parent</a>%</b> |
        <b class="alert">%<a href="../shorthands.htm#blockparent">Block Parent</a>%</b>
<dt><big><b class="mainheading">Content Model</b></big>
    <dd><b class="alert">%<a href="../shorthands.htm#inlinecontent">In-line Content</a>%</b>
</dl>


<a name="tips"></a>
<big><b class="mainheading">Tips &amp; Tricks</b></big>
<ul>
    <li>Although the above example demonstrates the use of BDO by reversing
        the direction of some English content (a rather cheap visual trick),
        please remember that this is not its intended semantic purpose.
</ul>

<a name="peculiar"></a>
<big><b class="mainheading">Browser Peculiarities</b></big>
<ul>
    <li><a href="../../../testing/html/tags/b/bdo-bp1.htm">[Test]</a>
        Opera 4-6.x (so far) only offers generalized support for BDO (only
        class/id/style/event attributes.) It does not have any element-specific behaviors.
    <li><a href="../../../testing/html/tags/b/bdo-bp1.htm">[Test]</a>
        Netscape 6.0 only offered generalized support for BDO - it only supported 
        class/id/style/events, but did not offer any element-specific behavior. The 
        same thing could be said for any made-up element name. This changed in 6.1.
</ul>


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